• Title/Summary/Keyword: Cleaning agents

Search Result 114, Processing Time 0.027 seconds

Recovery of Silicon Wafers from the Waste Solar Cells by H3PO4-NH4HF2-Chelating Agent Mixed Solution (인산-산성불화암모늄-킬레이트제 혼합용액에 의한 폐태양전지로부터 실리콘웨이퍼의 회수)

  • Koo, Su-Jin;Ju, Chang-Sik
    • Korean Chemical Engineering Research
    • /
    • v.51 no.6
    • /
    • pp.666-670
    • /
    • 2013
  • Recovery method of silicon wafer from defective products generated from manufacturing process of silicon solar cells was studied. The removal effect of the N layer and antireflection coating (ARC) of the waste solar cell were investigated at room temperature ($25^{\circ}C$) by variation of concentration of $H_3PO_4$, $NH_4HF_2$, and concentration and types of chelating agent. Removal efficiency was the best in the conditions; 10 wt% $H_3PO_4$ 2.0 wt% $NH_4HF_2$, 1.5 wt% Hydantoin. Increasing the concentration of $H_3PO_4$, the surface contamination degree was increased and the thickness of the silicon wafe became thicker than the thickness before surface treatment because of re-adsorption on the silicon wafer surface by electrostatic attraction of the fine particles changed to (+). The etching method by mixed solution of $H_3PO_4$-$NH_4HF_2$-chelating agents was expected to be great as an alternative to conventional RCA cleaning methods and as the recycle method of waste solar cells, because all processes are performed at room temperature, the process is simple, and less wastewater, the removal efficiency of the surface of the solar cell was excellent.

A Study on the Analysis of Urban Parks Management in the Busan City - Focusing on the Main Agent of Management - (부산광역시 도시공원의 관리운영 실태 분석에 관한 연구 - 관리주체측면을 중심으로 -)

  • Kim, Yeong-Ha;An, Yang-Wook;Park, Seung-Burm
    • Journal of the Korean Institute of Landscape Architecture
    • /
    • v.40 no.6
    • /
    • pp.127-139
    • /
    • 2012
  • This study aims to figure out the main agent of management in the 69 recently constructed neighborhood parks in Busan, and to analyze the present status of the main agents. For this purpose, the work resources on park and landscape management, interview to related staff, and the budget on urban parks were found as the main agents of management. In case the parks were managed by consignment or by other separate organization, this study collected resources through the homepage or personal visits. As a result for the management method on parks, about 48 parks(69.6%) were under direct management by the local governments' main office and its business offices. Eighteen parks(26.1%) were commissioned to corporation or private organizations and three parks(4.3%) were operated by both direct and commissioned management. Because of the overall management result on urban parks, the company under outsourced management is not sufficient for a comprehensive management. Such is mainly focused on the maintenance like landscape or cleaning, but have fewer programs for the users. Forty-six parks cared by the local governments are mainly small sized neighborhood parks. For the management, contract workers or short-term workers are hired. It demonstrates an urgent need to improve professional personnel and organizational system for park management. In addition, any educational or cultural facility in the park is managed by separate institutions. Thus, it is not controlled as a park facility but an independent facility with separate controls. Moreover, to solve such problems, it needs legalization on the proper employment for parks, institutional improvement, cooperative network with NGO, planning and development of the program used according to the change of time, and customer oriented program management.

A literal study on the Gu-Chang (구창의 문헌연구)

  • Jung Han Sol;Park Jong Hoon;Ryuk Sang Won;Lee Kwang Gyu
    • Journal of Physiology & Pathology in Korean Medicine
    • /
    • v.16 no.1
    • /
    • pp.32-44
    • /
    • 2002
  • Gu-Chang is a disorder characterized by recurring ulcers confined to the oral mucosa. Despite much clinical and research attention, the causes remain poorly understood. In this paper, we will compare Gu-Chang with Recurrent Aphthous Stomatitis(RAS) in order to know what is the similiarity between Gu-Chang and RAS. So we will arrange various oriental and western medical literatures which are important. As a result of arrangement of the causes, symptoms and therapys of Gu-Chang, we can conclude through the studies as follows. 1. The etiologies of Gu-chang are following. In the Sthenia syndrome, there are evil heat of external factor, heat of heart and spleen, insomnia, heat of upper warmer, stress and diet, heat of lung and heart, excessive heat of upper warmer, inappropriate food intake, heat conveyance of organ, heat of stomach merdian, moistured heat of spleen and stomach and stasis of liver energy. In the Asthenia syndrome, there are deficiency of stomach energy, deficiency of upper warmer leading to heat, deficiency of middle warmer leading to cold, deficiency of lower warmer leading to heat, deficiency of middle energy, deficiency of blood, decreased fire and deficiency of soil, yin fire of lower warmer, deficiency of heart yin, deficiency of spleen yin and deficiency of qi and blood. 2. In western medicine the causes of RAS is presumed as local, microbial, systemic, nutritional, genetic, immunologic factors. 3. Once Gu-chang is compared with RAS, in the deficiency of yin leading to hyperactivity of fire, deficiency of yin leading to floating of fire and stasis of liver energy, recurring of Gu-chang is similar to RAS. Although recurring of Gu-chang due to tripple warmer of excessive fire has no recurrance, since there are the degree of Pain, site of lesion, dysphagia etc, it is similar to major RAS. It is may be believed that Sthenia Gu-chang is similar to major RAS, shape of recurring, site of lesion, degrree of Pain and white color of Asthenia Gu-chang are similar to minor RAS, but there is no similarity concerning herpes RAS in the literatures that describe the symptoms. 4. Generally, the treatment of Gu-chang is divided into Asthenia and Sthenia Syndrome. The method of cure to Sthenia syndrome is heat cleaning and purge fire, Asthenia syndrome is nourish yin to lower and adverse rising energy and strength the middle warmer and benefit vital energy. 5. Following is the medication for Sthenia syndrome. Heat of heart and spleen is Do Jok San, Yang Gyek San, Juk Yup Suk Go Tang, evil heat of external factor is Yang Gyek San Ga Gam, Stasis of liver energy is Chong Wi Fae Dok Yum, moistured heat of spleen and stomach is Chong Gi Sam Syep Tang. The medication for Asthenia Syndrome is following. Deficiency of upper warmer leading to heat is Bo Jung Ik Gi Tang, deficiency of middle warmer leading to cold is Bu Ja Lee Jung Tang, deficiency of lower warmer leading to heat is Yuk Mi Ji Hwang Tang, deficiency of yin leading to hyperactivity of fire is Ji Baek Ji Hwang Hwan, deficiency of yin leading to floating of fire is Lee Jung Tang Ga Bu Ja Medicine for external use were Yang Suk San, Boo Wyen San, Rok Po San, Yoo Hwa San ate. 6. In western medicine, there is no specific treatment for RAS, and management strategies depend on dinical presentation and symptoms and includes antibiotics, oral rinses, glucocorticoids, immunomodulatory drugs, vitamines, analgesics, laser and antiviral agents.

Using Platforms as Market Creation Strategies for Small and Medium-Sized Service Robotics Companies in South Korea: The ROBOPRINT Case Study (국내 중소 서비스용 로봇 기업의 플랫폼을 이용한 시장 창출 전략: 로보프린트 사례연구)

  • Oh, Soo Jung
    • Korean small business review
    • /
    • v.43 no.2
    • /
    • pp.59-86
    • /
    • 2021
  • The platform concept has been used for business operations in various forms: product platforms, transaction platforms and industry platforms. All these platforms have common characteristics of having 'core' that is reused frequently and 'peripherals' that are less reusable and changed often. Companies use platforms to enable efficient development and creation of product family, transactions and innovation. These platforms provide new opportunities for many small and medium-sized companies (SMEs) by bringing changes to traditional industrial structures focused on the products rather than platforms. The service robotics industry in South Korea is mainly composed of technology-intensive SMEs due to its small market size. Although these SMEs succeed in developing technologies, they have difficulties creating and expanding markets to sell products. Thus, this study addresses the characteristics and problems of the South Korean service robotics industry and analyses how ROBOPRINT, one of the SMEs in the service robotics industry, successfully creates and continuously expands the service robot market by adopting platform concept. The results indicate that ROBOPRINT has been applying two types of platforms: product and transaction platforms. First, ROBOPRINT created art robots that were apartment mural service robots. Rather than selling art robots, the company developed various robots such as painting robots, building exterior wall-cleaning robots by reusing the core technology of the robots. The company also developed various robots according to the buyers request. In addition, the company used the robots to directly provide apartment mural services for customers. This mural service has been extended into various areas, not only in apartments but also in soundproof walls, underground passages, and retaining walls. Besides, ROBOPRINT added new services continuously by developing technologies such as virtual reality. Second, ROBOPRINT mediated mural service buyers and mural designers. This platform reduced buyers' workload, which necessitates requesting mural services to ROBOPRINT and searching for mural designers. For designers, this opened up new opportunities to participate in the mural business. The platform attracted both mural buyers and designers who were scattered before. Finally, ROBOPRINT seeks to expand the platform's scope to outside company. To share internally reused ROBOPRINT's technology with other companies, the company participated in Daegu city's 'New Technology Platform Industry'. Furthermore, ROBOPRINT is trying to share the service platform by leasing robots to other companies. This allows external agents to develop technologies and provide services by reusing resources from ROBOPRINT. This study contributes to existing theories by showing that SMEs continuously create and expand markets by building various platforms. Moreover, it provides useful implications for practitioners by describing the firm's specific platform-building strategy.